1. Field of the Invention
The present invention relates to a substrate having a semiconducting layer, to an electronic component which includes this substrate, to an electronic circuit which includes at least one electronic component of this type, to a printable composition and to processes for producing a semiconducting substrate.
2. Description of the Related Prior Art
The semiconducting (active) components of microchips usually consist of perfect single crystals of high-purity semiconducting inorganic substrates/materials, such as silicon or germanium. The functionality of these components is based on the electrical interface properties between differently semiconducting layers or domains which are produced by n-doping or p-doping of the substrates. However, this targeted doping requires complex lithographic masking, etching and ion implantation processes, including the patterning of the substrates with the aid of photoresists. However, components produced in this way, on account of the complex fabrication methods, are not suitable for applications in which the price of the components is the primary factor.
One possible way of producing semiconducting substrates and components based thereon which can be implemented without complex doping measures in semiconductor fabrication consists in using semiconducting organic polymers, such as polyvinylcarbazoles, polythiophenes, polyanilines, poly-p-phenylenes and poly-para-phenylvinylidenes (PPVs) and the like. Substrates based on semiconducting organic polymers of this type can be produced, as described in PCT applications WO 99/39373 or WO 99/19900, by semiconducting organic polymers which can be used as n-conductors or p-conductors being dissolved in an organic solvent and these mixtures being printed onto a substrate in layers by means of conventional inkjet printing technology. However, drawbacks of using organic polymers of this type include their low conductivity or the low charge carrier mobility, the fact that they are relatively expensive to produce and the low stability of doped materials with respect to environmental influences. Therefore, in particular they are not suitable for low-cost applications for semiconducting components and/or circuits.
Furthermore, German laid-open specifications DE 198 54 938 and DE 199 05 694 have disclosed a component which includes a first layer, a second layer and an interlayer located therebetween, the interlayer containing a first and/or a second material, as well as at least one substance which has a different conductivity than the first and/or second material being colloidally dissolved therein.
German laid-open specification DE 195 02 541 has disclosed an electroluminescent system which includes a light-emitting substance. In this context, it is provided that the light-emitting substance is formed by inorganic particles with grain sizes in the nanometer range which are connected to one another by means of organic spacers.
European patent application EP 0 777 279 describes an interlayer in electroluminescent arrangements which contain finely particulate inorganic nanoparticles.
Furthermore, PCT application WO 00/20916 has disclosed electrical, chemical and mechanical structures which are based on nanoparticles.
Thin Solid Films, 349 (1999), pages 105-109 has disclosed the deposition and characterization of composite layers of CdS and polyanilines. Applied Physics Letters, 74 (1999), No. 16, pages 2262-2264 describes the synthesis of amorphous GaN nanoparticles by the in situ thermal decomposition of cyclotrigallazane enclosed in a polymer and the photoluminescence of the nanoparticles. Applied Physics Letters, 70 (1997), 18, pages 2335-2337 investigates the photoluminescence and electroluminescence of ZnS:Cu nanocrystals in polymeric networks.